When you wrote pubsub, did you mean “the observer design pattern”? If so, please try to adopt a more formal lexicon and use terminology familiar to more developers. If not, please describe what a “pubsub” is.
No, I don't mean the observer pattern. I mean publisher subscriber pattern.
Observer pattern is fine, because there is still a link between the execution flow; basically any time you register a callback you're using the observer pattern.
Pubsub adds a middleware, typically in the form of a message passing framework, so that both publisher and subscriber aren't necessarily aware of each others existence. The publisher throws its data into the framework hoping someone finds it useful, and the subscriber listens for those messages hoping someone is publishing them. Think of it like multithread asynchronous goto of your execution flow, except with a lot more boilerplate.